The Gateshead Millennium Study is a birth cohort of children born between June 1999 and May 2000. 1029 children born to 1011 mothers were recruited into the study which looked to find reasons for the problem of weight faltering in infancy. Since then, the study has also looked at iron deficiency, breastfeeding, weaning, food preferences, repetitive behaviours, physical activity, parenting styles and food knowledge. Up until school age we asked the parent/main carer to provide information by completing questionnaires. Since then we have visited the children at ages 7, 9 and 12 years old in school, and asked them to complete questionnaires too. This has yielded data on topics such as sports club participation, eating attitudes, mental health, home environment, food knowledge and how they feel about eating. We have also measured their physical activity, body composition and food intake.

A new data sweep aims to build on this previous research by repeating earlier measures at age 15-16 years. This includes physical activity, sedentary behaviour, dietary intake, and behaviour and attitudes. The primary focus of this study is sedentary behaviour; this appears to have an important independent effect on cardiometabolic health and public health efforts are being made to promote breaks in sitting. However, there is a dearth of evidence in this field, and the evidence from this study will contribute towards future interventions. Dietary intake is equally important to health. We will continue to measure dietary intake, as well as important aspects of mental health, specifically quality of life and depression, which are associated with obesity in children, and the prevalence other lifestyle behaviours of early smoking and alcohol-drinking which can be risk factors for later physical and mental health problems. Impaired development in early life may lead to poor respiratory function and high blood pressure in later life, but as it is not known when these changes may start to occur, we will again measure lung function and blood pressure.